1. Field of the Invention
The present invention relates generally to the field of voltage converters and more particularly to a high-efficiency, charge-and-add adjustable converter.
2. Description of the Field
Converting from a low voltage to a high voltage, and from a high voltage to a low voltage is one of the outmost important fields in the electronics art. There are few electronic or electrical apparatus that will work without some type of power converting, since all of them need a specific and defined voltage for a proper operation. Among all converters, DC-DC converters represent the largest number. DC-DC converters vary by a purpose, functionality, technique, etc. DC-DC converters are distinguished by power capability, input/output voltages, and the technique by which the converting occurs. Converters also compete by how efficiently they converter one voltage into another.
DC-DC charge pump designs have been around the last thirty years. Among various topologies, a switched-capacitor voltage multiplier circuit is known in the art. Since introduction the switched-capacitor circuitry, the emphasis has been on obtaining the most voltage gain with minimum components. There are a number of inventions describing a charge pump DC-DC as an inverter, splitter or booster known in the art. They can double voltage, triple voltage, halve voltages, invert voltages, fractionally multiply or scale voltages such as 3/2×, 4/3×, etc. and generate arbitrary voltages.
The best of the prior art charge pump converters can deliver up to about 250 mA at around 75% efficiency. Most of their applications are in battery-based systems such as cellular phones, pages, Bluetooth systems, portable electronic equipment, and handheld instruments. A major application is to power white LEDs for backlighting LCD panels. The basic charge pump lacks regulation, so virtually all present-day charge pump converters either add linear regulation or charge-pump modulation.
What is badly needed is a charge-and-add converter with pulse frequency modulation which is one of the most efficient power converting devices that can deliver output voltage with up to 98% efficiency. This efficiency, with all power components (switches and capacitors), is the same depending on chosen frequency of switching and how often a charge-and-add cycle occurs.
The charge-and-add converter of the present invention is an innovative topology among many approaches to the charge pump design, the switch-capacitor circuits. It allows converting much power from a low voltage, high current source into a load that required a higher voltage and not as much current. The charge-and-add can be use to build multi-kilowatt converters and power an electrical car, convert a low voltage produced by a photo-cell into a more useful high voltage to power home appliances and machinery.